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An Environmental Protection Agency spokeswoman on Thursday denied that former EPA chief Lisa Jackson used a New Jersey government email account while she was heading the federal agency, following claims by a Washington attorney that Jackson may have been trying to use the account to skirt records requests.

The New Jersey account turned up amid thousands of pages of emails released by the administration late last week. Chris Horner, a senior fellow at the Competitive Enterprise Institute, said the use of alias and non-federal government accounts suggests an attempt to skirt federal records laws and requests.

Jackson, who left at the beginning of President Obama's second term, has already been under scrutiny for using the alias "Richard Windsor" in emails. The documents released last week showed that, in at least one case, Jackson also used her New Jersey government email account to forward her Richard Windsor account a New York Times article in July 2009.

However, EPA spokeswoman Alisha Johnson told FoxNews.com on Thursday that, upon further inspection, it appears Jackson's New Jersey email account only turned up because that was the user name for the New York Times account she had set up.

"That (New Jersey) account was closed when she left her position" in New Jersey, Johnson said.

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    The email that showed up in the documents would have been sent months after Jackson left the New Jersey Department of Environmental Protection.

    Horner had raised concerns about that account, in addition to his longstanding concerns about the use of an alias email, which has been thoroughly documented.

    In response to the EPA's explanation, Horner said in an email Thursday that "we're dealing with someone who has earned no benefits of any doubts."

    The EPA has claimed that EPA administrators for more than a decade have been assigned both "a public account and an internal account."

    "The email address for the public account is posted on EPA's website and is used by hundreds of thousands of Americans to send messages to the administrator. The internal account is an everyday, working email account of the administrator to communicate with staff and other government officials," the EPA said in an earlier statement. "Given the large volume of emails sent to the public account -- more than 1.5 million in fiscal year 2012, for instance -- the internal email account is necessary for effective management and communication between the administrator and agency colleagues."

    The statement explained that both accounts are reviewed when responding to records requests.

    The latest development comes after the EPA confirmed that Region 8 Administrator James Martin plans to resign effective Friday.

    An EPA spokeswoman said he was resigning merely "for personal reasons." But Horner and Republican Sen. David Vitter claimed the resignation was tied to questions over the use of a personal email account to conduct "official business."

    Vitter and Rep. Darrell Issa, R-Calif., claimed documents showed he used his private me.com account to confirm a meeting with the general counsel for the Environmental Defense Fund.

    The EPA, according to Politico.com, downplayed the communication as a one-time occurrence.

    But the Republican lawmakers wrote in a recent letter that "it does not appear that this transaction was an isolated incident."